Dry powder inhaler

ABSTRACT

A dry powder inhaler (10) having a chamber (26) divided into first and second blister compartments (28, 30) for storing unused and used portions (34, 36) of a blister strip (12) is provided. A moveable dividing wall (32) separates the first and second blister compartments. One or more arcuate supporting surfaces (38, 40, 42) are disposed in either the first and/or the second blister compartments and these surfaces support the used or unused blister strip during successive actuations of the inhaler. Use of the arcuate supporting surfaces facilities compact coils of unused and used portions of blister strip, thereby reducing the size of the chamber required for the inhaler.

This application is a U.S. national phase application under 35 U.S.C. of§ 371 of International Application No. PCT/EP2016/067208, filed Jul. 19,2016, which claims priority of European Patent Application No.15177556.6, filed Jul. 20, 2015, the disclosure of which is herebyincorporated by reference herein.

The present invention relates to an inhalation device for oral or nasaldelivery of medicament in powdered form. More specifically, theinvention relates to a dry powder inhaler in which powdered medicamentis stored within a strip of blisters. The invention also relates to aninhaler containing a strip of blisters each having a puncturable lid andcontaining a dose of medicament for inhalation by a user of the deviceaccording to the invention.

Oral or nasal delivery of a medicament using an inhalation device is aparticularly attractive method of drug administration as these devicesare relatively easy for a patient to use discreetly and in public. Aswell as delivering medicament to treat local diseases of the airway andother respiratory problems, they have more recently also been used todeliver drugs to the bloodstream via the lungs, thereby avoiding theneed for hypodermic injections.

It is common for dry powder formulations to be pre-packaged inindividual doses, usually in the form of capsules or blisters which eachcontain a single dose of the powder which has been accurately andconsistently measured. A blister is generally cold formed from a ductilefoil laminate or a plastics material and includes a lid which ispermanently or peelably sealed around the periphery of the blisterduring manufacture and after the dose has been introduced into theblister.

A foil blister is preferred over capsules as each dose is protected fromthe ingress of water and penetration of gases such as oxygen in additionto being shielded from light and UV radiation, all of which can have adetrimental effect on the delivery characteristics of the inhaler if adose becomes exposed to them. Therefore, a blister offers excellentenvironmental protection to each individual drug dose.

Inhalation devices that receive a coiled blister strip comprising anumber of blisters each of which contain a pre-metered and individuallypackaged dose of the drug to be delivered are well known. Actuation ofthe device causes a mechanism to breach or rupture a blister, such as bypuncturing it or peeling the lid off, so that when the patient inhales,air is drawn through the blister entraining the dose therein that isthen carried out of the blister through the device and via the patient'sairway down into the lungs. Pressurized air or gas or other propellantsmay also be used to carry the dose out of the blister. Alternatively,the mechanism that punctures or opens the blister may push or eject thedose out of the blister into a receptacle from which the dose maysubsequently be inhaled.

It is advantageous for the inhaler to be capable of holding a number ofdoses to enable it to be used repeatedly over a period of time withoutthe requirement to open and/or insert a blister into the device eachtime it is used. Therefore, many conventional devices include means forstoring a number of blisters each containing an individual dose ofmedicament. When a dose is to be inhaled, an indexing mechanism moves apreviously emptied blister away from the opening mechanism so that afresh one, a target blister, is moved into a position ready to be openedfor inhalation of its contents. An inhaler of this type is known fromthe Applicant's own international patent application which published asWO2005/037353 A1.

The device known from WO2005/037353 A1 has already been modified so asprovide a fully integrated device, i.e. one in which the used blistersare retained within its housing so that a user never has to come intodirect contact with the blister strip.

In one modified embodiment, known from the Applicant's own previousapplication that has now been published as WO2009/007352 A1, there isprovided a flexible and resilient spiral element mounted within thehousing of the device into which the used portion of the blister stripis directed so that, as the strip is gradually used up, the spiralexpands as more and more of the strip is fed or pushed into it betweenits coils.

Like the present invention, the device in WO2009/007352 A1 has adividing wall to separate the interior of the housing into used andunused blister compartments. The dividing wall is rigid and slideablymounted so that the size of the unused and used blister compartmentschanges relative to each other as the number of blisters that are usedincreases and the number of unused blisters decreases. A moveable wallis also known from US 2010/0288278 (Valois S.A.S.).

WO09/007352 A1 also describes an embodiment in which used blisters arecrushed between the blister strip drive or indexing wheel and the innersurface of the casing of the device, which is also a feature of theinhaler of the present invention. As crushing takes place, i.e. as theused strip passes around the blister strip drive member, a curl orcurved form is imparted to the strip which helps it to coil up withinthe used blister compartment.

A full operation of the inhaler according to the present invention isdescribed in WO2012/069854 A1. The indexing mechanism is specificallydescribed in WO2009/092652 A1.

The disclosures of WO2005/037353 A1, WO09/007352 A1, WO2009/092652 A1and WO2012/069854 A1 are all incorporated herein by reference.

The present invention seeks to provide an inhalation device that retainsa used blister strip within the housing of the device, whilst optimisingthe internal configuration in order to enhance the compactness of thedevice.

According to a first aspect of the invention, there is provided aninhaler comprising

-   -   a housing,    -   a mouthpiece,    -   a blister strip having a plurality of blisters, each blister        containing, at least initially, a dose of medicament for        inhalation by a user via the mouthpiece,    -   a blister opening assembly for facilitating withdrawal of        medicament from a target blister of the blister strip,    -   an actuator mechanism operable to sequentially move each blister        into alignment with the blister opening assembly so as to become        said target blister,    -   the housing comprising a first blister compartment for storing        an unopened portion of the blister strip as a first coil, a        second blister compartment for receiving an opened portion of        the blister strip and coiling it into a second coil, and a        movable dividing wall separating the first and second blister        compartments,    -   the movable dividing wall being displaced progressively during        successive actuations of the inhaler, thereby causing the volume        of the first blister compartment to decrease progressively and        the volume of the second blister compartment to increase        progressively,    -   the inhaler further comprising an arcuate supporting surface        within the housing for supporting at least a portion of the        first or second coils.

Optionally, a radius of the arcuate supporting surface matches theradius of the first coil, at a stage in the life of the inhaler, whenthe diameter of the first coil is at a maximum.

Optionally, a radius of the arcuate supporting surface matches theradius of the first coil, at a stage in the life of the inhaler, whenthe sum diameter of the first and second coils is at a maximum.

Optionally, a radius of the arcuate supporting surface matches theradius of the second coil, at a stage in the life of the inhaler, whenthe diameter of the first coil is at or near a maximum.

The arcuate supporting surface may be disposed in, or form part of, thefirst blister compartment.

The arcuate supporting surface may be disposed in, or form part of, thesecond blister compartment.

Preferably, the arcuate supporting surface extends from an internalsurface of the housing. Alternatively, the arcuate supporting surfacemay extend from an internal wall within the housing.

Preferably, the arcuate supporting surface has a length equivalent to anarc of the first coil of at least 30 degrees when the diameter of thefirst coil is at a maximum.

Preferably, the position of the arcuate supporting surface relative tothe housing is fixed such that it is immoveable.

The first coil may be disposed intermediate the arcuate supportingsurface and the moveable dividing wall. Alternatively, the second coilmay be disposed intermediate the arcuate supporting surface and themoveable dividing wall.

Preferably, the inhaler further comprises a blister strip guide rib forcontrolling the direction of the used blister strip as it enters thesecond blister compartment, the used blister strip passing between theguide rib and an internal surface of the housing during successiveactuations of the inhaler. Ideally, the blister strip has a height a andthe guide rib is spaced apart from the internal surface of the housingby distance b, wherein distance b is less than height a.

Optionally, the inhaler further comprises a blister crushing member forat least partially squashing the blisters after they have been opened.

Preferably, the arcuate supporting surface has a thickness of up to 1mm. Preferably, the arcuate supporting surface is spaced apart from themoveable dividing wall.

Preferably, the arcuate supporting surface is inflexible or rigid.

Optionally, the movable dividing wall may be configured to facilitatethe formation of the second coil as the used portion of the blisterstrip enters the second blister compartment.

Preferably, the blister strip carries between 30 and 60 blisters.

Preferably, each blister has a dose payload of up to 100 mg, preferablyup to 50 mg, and more preferably between 10 and 25 mg.

According to a second aspect of the invention there is provided aninhaler, comprising

-   -   a housing,    -   a mouthpiece,    -   a blister strip having a plurality of blisters, each blister        containing, at least initially, a dose of medicament for        inhalation by a user via the mouthpiece,    -   a blister opening assembly for facilitating withdrawal of        medicament from a target blister of the blister strip,    -   an actuator mechanism operable to sequentially move each blister        into alignment with the blister opening assembly so as to become        said target blister,    -   the housing comprising a first blister compartment for storing        an unopened portion of the blister strip as a first coil, a        second blister compartment for receiving an opened portion of        the blister strip and coiling it into a second coil, and a        movable dividing wall separating the first and second blister        compartments,    -   the movable dividing wall being displaced progressively during        successive actuations of the inhaler, thereby causing the volume        of the first blister compartment to decrease progressively and        the volume of the second blister compartment to increase        progressively,    -   the inhaler further comprising an arcuate supporting surface        within the housing for supporting at least a portion of the        first coil,    -   characterised in that a radius of the arcuate supporting surface        matches the radius of the first coil, at a stage in the life of        the inhaler, when the diameter of the first coil is at a        maximum.

According to a third aspect of the invention, there is provided aninhaler, comprising

-   -   a housing,    -   a mouthpiece,    -   a blister strip having a plurality of blisters, each blister        containing, at least initially, a dose of medicament for        inhalation by a user via the mouthpiece,    -   a blister opening assembly for facilitating withdrawal of        medicament from a target blister of the blister strip,    -   an actuator mechanism operable to sequentially move each blister        into alignment with the blister opening assembly so as to become        said target blister,    -   the housing comprising a first blister compartment for storing        an unopened portion of the blister strip as a first coil, a        second blister compartment for receiving an opened portion of        the blister strip and coiling it into a second coil, and a        movable dividing wall separating the first and second blister        compartments,    -   the movable dividing wall being displaced progressively during        successive actuations of the inhaler, thereby causing the volume        of the first blister compartment to decrease progressively and        the volume of the second blister compartment to increase        progressively,    -   the inhaler further comprising an arcuate supporting surface        within the housing for supporting at least a portion of the        first coil,    -   characterised in that a radius of the arcuate supporting surface        matches the radius of the first coil, at a stage in the life of        the inhaler, when the sum diameter of the first and second coils        is at a maximum.

According to a fourth aspect of the invention, there is provided aninhaler, comprising

-   -   a housing,    -   a mouthpiece,    -   a blister strip having a plurality of blisters, each blister        containing, at least initially, a dose of medicament for        inhalation by a user via the mouthpiece,    -   a blister opening assembly for facilitating withdrawal of        medicament from a target blister of the blister strip,    -   an actuator mechanism operable to sequentially move each blister        into alignment with the blister opening assembly so as to become        said target blister,    -   the housing comprising a first blister compartment for storing        an unopened portion of the blister strip as a first coil, a        second blister compartment for receiving an opened portion of        the blister strip and coiling it into a second coil, and a        movable dividing wall separating the first and second blister        compartments,    -   the movable dividing wall being displaced progressively during        successive actuations of the inhaler, thereby causing the volume        of the first blister compartment to decrease progressively and        the volume of the second blister compartment to increase        progressively,    -   the inhaler further comprising an arcuate supporting surface        within the housing for supporting at least a portion of the        second coil,    -   characterised in that a radius of the arcuate supporting surface        matches the radius of the second coil, at a stage in the life of        the inhaler, when the diameter of the first coil is at or near a        maximum.

This coincides with a stage in the life of the inhaler when the diameterof the second coil is at a minimum.

According to a fifth aspect of the invention, there is provided aninhaler, comprising a housing, a mouthpiece extending from or mounted tothe housing, a blister strip having a plurality of blisters, eachblister containing, at least initially, a dose of medicament forinhalation by a user via the mouthpiece, a blister opening assembly forfacilitating withdrawal of medicament from a target blister of theblister strip, an actuator mechanism operable to sequentially move eachblister into alignment with the blister opening assembly so as to becomesaid target blister, the housing comprising a first blister compartmentfor storing an unopened portion of the blister strip as a first coil, asecond blister compartment for receiving an opened portion of theblister strip and coiling it into a second coil, and a movable dividingwall separating the first and second blister compartments, the movabledividing wall being displaced progressively during successive actuationsof the inhaler, thereby causing the volume of the first blistercompartment to decrease progressively and the volume of the secondblister compartment to increase progressively, the inhaler furthercomprising an arcuate supporting surface in the first blistercompartment for supporting at least a portion of the first coil, asecond said arcuate supporting surface in the first blister compartmentfor supporting a further portion of the first coil and a third saidarcuate supporting surface in the second blister compartment forsupporting a portion of the second coil.

Preferably, the inhaler further comprises a blister strip guide rib forcontrolling the direction of the used blister strip as it enters thesecond blister compartment, the used blister strip passing between theguide rib and an internal surface of the housing during successiveactuations of the inhaler. Ideally, the blister strip has a height a andthe guide rib is spaced apart from the internal surface of the housingby distance b, wherein distance b is less than height a.

Embodiments of the invention will now be described, by way of exampleonly, with reference to FIGS. 1 to 9 of the accompanying drawings, inwhich:

FIG. 1 is an exploded perspective view showing the individual componentsof an inhaler according to the invention;

FIGS. 2a to 2e is a sequence of drawings to show the general functionand operation of the inhaler;

FIG. 3 is a cross-sectional side view of the inhaler, showing inparticular a coiled portion of unused blister strip in a first blistercompartment of the inhaler;

FIG. 4 is the cross-sectional side view of the inhaler of FIG. 3 butwith the coiled blister strip removed for clarity, at the stage in thelife of the inhaler when a diameter of the coiled portion of unusedblister strip is at a maximum;

FIG. 5 is the cross-sectional side view of the inhaler of FIG. 3 againwith the coiled blister strip removed, at the stage in the life of theinhaler when the sum diameter of the coiled portion of unused blisterstrip and a coiled portion of used blister strip is at a maximum;

FIG. 6 is the cross-sectional side view of the inhaler of FIG. 3 yetagain with the coiled blister strip removed, at the stage in the life ofthe inhaler when the diameter of the coiled portion of used blisterstrip is at a maximum;

FIG. 7 is a graph showing the space requirements within the inhaler forthe unused and used blister strip throughout the life of the inhaler,without blister crushing;

FIG. 8 is a graph similar to that in FIG. 8, but with blister crushingincorporated into the inhaler, demonstrating the effect of blistercrushing on the space requirements within the inhaler; and

FIG. 9 is a schematic close-up view of the used blister strip enteringinto a second blister compartment and coiling back onto itself, to forman additional coil.

Referring to FIGS. 1 and 2 of the accompanying drawings, there is showna dry powder inhaler 10 for dispensing powdered medicament from ablister strip 12. The inhaler 10 comprises a housing 14 formed from twoshell portions 14 a, 14 b a cap 16 pivotally mounted to the housing 14for rotation about a first axis of rotation A, a mouthpiece 18 pivotallymounted to the housing 14 about a second axis of rotation B, a blisterpiercing member 20 depending from the mouthpiece 18 for piercing theblister strip 12, an indexing system for advancing the blister strip 12past the blister piercing member 20 and an actuating lever 22 operableto cause both indexing and piercing of the blister strip 12.

The cap 16 is moveable, from a closed position in which the cap 16covers and protects the mouthpiece 18, to a fully open position, and ina direction indicated by arrow “R” in FIG. 2(a), in which the mouthpiece18 is exposed to enable a user to inhale a dose of medicament throughthe mouthpiece 18 from the blister strip 12.

The cap 16 is rotated into its fully open position in the direction ofarrow “R”. The actuating lever 22 is revealed as soon as the cap 16 isrotated out of its closed position. The user then applies pressure tothe actuating lever 22, so that it rotates in the direction indicated byarrow “S” in FIG. 2(b).

During initial rotation of the actuating lever 22 through a firstportion of its stroke into the position as it is shown in FIG. 2(b), theblister strip 12 is indexed so as to move an unused blister intoalignment with the blister piercing member 20.

When the actuating lever 22 is rotated through a second portion of itsstroke beyond the position shown in FIG. 2(b) and after having completedthe first portion of its stroke, in the direction of arrow “T” in FIG.2(c), the blister strip 12 remains stationary but the mouthpiece 18 isnow pivoted so that the blister piercing member 20 pierces the lid ofthe previously aligned blister.

Once the actuating lever 22 is in the position shown in FIG. 2(c), theuser now inhales through the mouthpiece 18, as shown by arrows indicatedby “U” in FIG. 2(d).

After inhalation, the user rotates the cap 16 in the opposite direction,i.e. in the direction indicated by “V” in FIG. 2(e). During thismovement, the cap 16 engages with the actuating lever 22 so that theactuating lever 22 also returns to its initial position as shown in FIG.2(a), the blister strip remaining stationary during this return movementof the actuating lever 22.

It should be noted that the cap 16 is ‘passive’ in the sense that it canbe opened and closed freely without performing the function of indexingof the blister strip 12 or causing a blister piercing member 20depending from the mouthpiece 18 to pierce the lid of an alignedblister. However, although the cap 16 is passive, it does perform thefunction of re-setting the actuating lever back to its original positionin the event that the actuating lever 22 is depressed prior to closingthe cap 16.

The cap 16 and actuating lever 22 are configured so that, when the cap16 is in its closed position and the actuating lever 22 has returned toits initial position, the cap 16 overlies the actuating lever 22 whichis pressed by a user to operate the device. This prevents a user fromattempting to operate the device by rotating the actuating lever 22prior to opening the cap 16.

As previously mentioned, the inhaler 10 has an indexing mechanism thathas previously been described in WO2009/092652 A1 and a thus furtherdetailed description will be omitted here.

The indexing mechanism comprises a blister strip drive member orindexing wheel 24, around which the used blister strip travels, andwhich drives the blister strip 12 onwards. The indexing wheel 24 mayalso be used to squeeze the used blister cavities as they pass aroundit, thereby at least partially crushing them. This is achieved byenlarging the axle or hub of the indexing wheel 24 so that the distancebetween the hub and the casing or wall of the inhaler 10, or a componentfixed to the casing, is less than the maximum height of a blistercavity. As the blister cavities are entrained between spokes of theindexing wheel 24, onward rotation of the indexing wheel 24 causes thecavities to be at least partially squashed or sandwiched between theenlarged hub of the indexing wheel 24 and the casing of the inhaler 10.The advantage of at least partially crushing the empty blister cavitiesis that they then take up less space when coiled within the used blistercompartment of the device as the coiled strip has a smaller radius.Furthermore, a natural curvature is imparted to the strip, both as aresult of being fed around the indexing wheel 24 and also as a result ofthe crushing of the blister cavities. This encourages the used portionof the blister strip 12 to coil more readily. It is also apparent that,when the blister cavities have been crushed, the cavity is moreresilient to denting at the point at which the spoke of the indexingwheel 24 contacts the strip, i.e. at the root where the blister cavitymeets the remainder of the blister strip 12. Therefore, a more positiveand precise drive of the blister strip 12 is achieved when the blistershave been crushed.

Within the housing 14, a chamber 26 is separated into first and secondcompartments 28, 30 by a rigid dividing wall 32. The unused portion ofblister strip 12 is stored within the first blister compartment 28 as afirst coil 34 and the used portion of blister strip 12 is received intothe second blister compartment 30 to form a second coil 36. The dividingwall 32 is slideably mounted within the chamber 26 so that, as more ofthe blisters are used, the force of the used coil 36 of blisters in thesecond blister compartment 30 presses against the dividing wall 32 andpushes it so as to enlarge the space for the used blisters and reducethe space previously occupied by the unused blisters.

It is here where the invention lies. The configuration of the interiorof the housing 14 has been optimised to minimise the space required forthe first and second blister compartments 28, 30, thereby reducing theoverall size of the inhaler 10.

The inhaler 10 comprises three arcuate supporting surfaces 38, 40, 42within the housing 14 for supporting at least a portion of the firstcoil 34, of the second coil 36, or both the first and second coils 34,36 during successive actuations of the inhaler 10. In this embodiment,three distinct arcuate supporting surfaces 38, 40, 42 are provided, butany one or two combinations of the arcuate supporting surfaces 38, 40,42 could feasibly be used. It is only when all three arcuate supportingsurfaces 38, 40, 42 are used that the configuration is optimised. Withonly one or two arcuate supporting surfaces 38, 40, 42, theconfiguration is improved so that less space is required for the unusedand used portions of blister strip 12, but it is not an optimumconfiguration, which is preferable.

FIG. 3 shows the coil 34 of unused blister strip 12 after one or twoactuations have taken place but before the second coil 36 has begun toform in the second blister compartment 30. The diameter of the firstcoil 34 is just less than its maximum.

FIG. 4 indicates the coil 34 of unused blister strip 12 at or near itsmaximum diameter but with enough used blister strip in the secondblister compartment 30 to form the second coil 36. In FIG. 4, a firstarcuate supporting surface 38 is seen to support the theoreticaloutermost spiral of the first coil 34. The first arcuate supportingsurface 38 forms part of the first blister compartment 28. The firstarcuate supporting surface 38 extends from an internal wall of theinhaler 10, proximate to the indexing wheel 24.

In this position, the first arcuate supporting surface 38 supports thefirst coil 34 in a substantially central position within the inhaler 10,urging the moveable dividing wall 32 to the right hand side of theinhaler 10 as viewed in FIG. 4. The first arcuate supporting surface 38has a length equivalent to an arc of the first coil 34 of at least 30degrees when the diameter of the first coil 34 is at a maximum. Thislength of arcuate supporting surface provides sufficient support for thefirst coil 34 to hold it in place initially but without unnecessarilyincreasing the complexity of the design of the inhaler 10.

A second arcuate supporting surface 40 supports the second coil 36. Thesecond arcuate supporting surface 40 forms part of the second blistercompartment 30. The second arcuate supporting surface 40 is situated inthe vicinity of the exit region of the indexing wheel 24. The length ofthe second arcuate supporting surface 40 is equivalent to an arc of thesecond coil 36 of at least 30 degrees when the diameter of the firstcoil 34 is at a maximum.

Thus, the configuration of the first and second blister compartments 28,30 is specific to the stage in the life of the inhaler 10 when thediameter of the first coil 34 is at or near a maximum. It is also atthis time, that the diameter of the second coil 36 is at a minimum. Atthis stage, the radius of the first arcuate supporting surface 38matches the radius of the first coil 34. Also, the radius of the secondarcuate supporting surface 40 matches the radius of the second coil 36.

Turning now to FIG. 5, a third arcuate supporting surface 42 extendsinwardly from an internal surface of the inhaler 10. The third arcuatesupporting surface 42 forms part of the first blister compartment 28.The third arcuate supporting surface 42 is situated in the vicinity ofthe entry region of the indexing wheel 24. Again, the length of thethird arcuate supporting surface 42 is equivalent to an arc of the firstcoil 34 of at least 30 degrees when the diameter of the first coil 34 isat a maximum.

In FIG. 5, the configuration of the first and second blistercompartments 28, 30 is specific to the stage in the life of the inhaler10 when the combined diameter of the first and second coils 34, 36 is ata maximum. At this stage, the radius of the third arcuate supportingsurface 42 matches the radius of the first coil 34.

In FIG. 6, all or almost all of the doses from the blister strip 12 havebeen dispensed from the inhaler 10. The configuration of the first andsecond blister compartments 28, 30 is specific to the stage in the lifeof the inhaler 10 when the diameter of the second coil 36 is at amaximum. This coincides with same stage as when the diameter of thefirst coil 34 is at or near a minimum.

With reference to FIG. 7, the diameter of the first coil is indicated atcurve 44, the diameter of the second coil at curve 46, and the sum ofthese two diameters, i.e. the sum diameter of the first and second coilsis indicated at curve 48.

At the beginning of the life of the inhaler 10 when few or no doses havebeen dispensed, and also up to substantially mid-way through the life ofthe inhaler, it is very important for the space within the first andsecond blister compartments 28, 30 to be tightly controlled or allocatedso as to minimise the internal volume required subsequently for thefirst and second coils 34, 36. If this did not happen, the curve 48indicating the sum diameter of the first and second coils 34, 36 wouldshift upwardly and would begin at a much higher point on the graph.Consequently, the space required for the first and second coils 34, 36when their combined diameters are at a maximum, i.e. the peak of the sumof diameters curve 48 occurring approximately mid-way through the lifeof the inhaler 10, would be higher. In brief, it is imperative that thecombined diameter of the first and second coils is as small as possibleat the start of the useful life of the inhaler.

At or towards the end of the life of the inhaler 10, the role of thearcuate supporting surfaces 38, 40, 42 becomes increasinglyinsignificant because there is less need now for the used blister stripto be coiled up tightly. In practice, the second coil 36 simply expandsto fill most, if not all, of the space available within the secondblister compartment 30.

When blister crushing is incorporated into the inhaler 10, as explainedearlier, this reduces the sum diameter of the first and second coils 34,36 generally throughout the life of the inhaler 10, as indicated in FIG.8. In particular, the space required for the first and second coils 34,36 when the combined diameter of the first and second coils 34, 36 is ata peak, is reduced compared to when no blister crushing is used.

Blister crushing does not affect the diameter of the first coil 34 sinceblister crushing takes place after blister piercing and dose inhalationhas occurred. It does affect the diameter of the coiling used blisterstrip, and facilitates a tighter second coil 36. Therefore, the sumdiameter of the first and second coils 34, 36 is less than when noblister crushing occurs.

It is clear from both FIGS. 7 and 8 that it is important to constrainthe first and second coils 34, 36 as much as possible in the earlystages of the life of the inhaler 10 in order to minimise the sumdiameter of the first and second coils 34, 36. This, in turn, minimisesthe amount of space required when the sum diameter of the first andsecond coils 34, 36 is at its peak (or maximum). This is achieved byemploying one or more the arcuate supporting surfaces 38, 40, 42described above.

None of the aforementioned arcuate supporting surfaces 38, 40, 42 formpart of the moveable dividing wall 32. For a period of time, the firstarcuate supporting surface 38 is near to the moveable dividing wall 32,as the moveable dividing wall 32 travels across the breadth of theinhaler 10 from right to left as viewed when looking at FIGS. 4, 5 and6. The second arcuate supporting surface 40 is separated from themoveable dividing wall 32 by the second coil 36. The third arcuatesupporting surface 42 is separated from the moveable dividing wall 32 bythe first coil 34.

In this embodiment of the invention, the moveable dividing wall 32comprises an elongate foot 50 which is attached to and integrally formedwith a baffle 52 that divides the chamber 26 within the inhaler 10 intothe first and second blister compartments 28, 30. An approximate centralregion of the foot 50 is attached to the baffle 52 so that it extends inopposite directions on either side of the baffle 52. The foot 50 isslideably received in a recess 54 formed in a wall of the housing 14 andis wider at its ends than in its centre where it joins the baffle 52 sothat contact with the walls of the recess 50 is primarily made with thewider ends of the foot 50.

The baffle 52 itself is generally ‘J’ shaped, with a linear body portion56 and an arcuate tail portion 58 extending from a lower end of thelinear body portion 56. The arcuate tail portion 58 is curved toencourage the incoming used blister strip within the second compartment30 to curl tightly into the second coil 36. The smaller the radius ofthe arcuate tail portion 58, the tighter the second coil 36 becomes. Theadvantage of this is that the resulting second coil 36 is smaller whenat its greatest radius than it would be otherwise.

Turning now to FIG. 9, a blister strip guide rib 60 is positioned in thesecond blister compartment 30. The blister strip guide rib 60 controlsthe direction of the used blister strip as it enters the second blistercompartment 30. A gap or channel exists between the blister strip guiderib 60 and the housing 14 to allow the used blister strip to passtherethrough during successive actuations of the inhaler 10. The size ofthe gap is important. If the blister strip 12 has a height a and theblister strip guide rib 60 is spaced apart from an internal surface ofthe housing 14 by a distance b, distance b must be less than height a.

The thickness of the blister strip guide rib 60 is critical. Too thinand the blister strip guide rib 60 is problematic during manufacturing.Too thick and the used blister strip will not coil tightly; instead theused blister strip will form an elongate (as opposed to rounded) loopthat pushes away from the blister strip guide rib 60 towards the centreof the chamber 26, before eventually beginning to coil. The resultingdiameter of the second coil 36 would therefore be a lot greater than itwould be otherwise, thereby increasing the combined diameter of thefirst and second coils 34, 36, and consequently increasing the internalvolume required for the used and unused blister strip 12. When thethickness of the rib is at an optimum value, as the used blister stripbegins to coil, it will coil back on itself, and engage the incomingused blister strip. The force acting on the incoming blister strip tomove it forward is consequently augmented by the force acting on thefree end of the blister strip 12. The inventors have found the optimumthickness of the blister strip guide rib 60 to be up to 1 mm.

In terms of impact on the overall internal volume required, the blisterstrip guide rib 60 has been found to be more influential than the threeaforementioned arcuate supporting surfaces 38, 40, 42. The third arcuatesupporting surface 42 is then most influential, followed by the firstarcuate supporting surface 38 and finally the second arcuate supportingsurface 40.

If no blister crushing were to be incorporated into the inhaler 10, thedevice would still benefit from one or more of the three arcuatesupporting surfaces 38, 40, 42 and/or the blister strip guide rib 60.However, the overall space required for the used and unused blisterstrip 12 when the combined diameter of the coiled used and unusedblister strip 12 is at a maximum, would be higher.

With higher dose payload blisters, optimisation of the internal spacerequired can still occur but again the peak sum diameter of the coiledused and unused blister strip 12 would be higher than it would beotherwise.

Optimisation would work for a 60 (sixty) dose inhaler 10 as well as a 30(thirty) dose inhaler 10. With a 30 dose inhaler 10, the entire devicecould in theory be made proportionally smaller. However, in reality,since the cost of tooling has already been paid for once for the 60 doseconfiguration and a 30 dose inhaler 10 would use common components, itwould be economically prudent to use the existing tooling. Furthermore,the question of optimising the internal space required for a 30 doseinhaler 10 would be rather moot simply because there would be plenty ofspace already available.

Many modifications and variations of the invention falling within theterms of the following claims will be apparent to those skilled in theart and the foregoing description should be regarded as a description ofthe preferred embodiments of the invention only. For example, althoughreference is made to a “mouthpiece”, the invention is also applicable todevices in which the dose is inhaled through the nasal passages.Therefore, for the purposes of this specification, the term “mouthpiece”should also be construed so as to include within its scope a tube whichis inserted into the nasal passages of a patient for inhalationtherethrough.

Furthermore, although the blister piercing member is described as beingattached to the mouthpiece so that the mouthpiece and the blisterpiercing member move together, it is also envisaged that the mouthpieceitself could remain stationary and the blister piercing element could bepivotally mounted to the mouthpiece so that the blister piercing memberrotates relative to the mouthpiece to pierce the lid of an alignedblister.

In another embodiment, the cap and the actuating member could becombined into a single component so that rotation of the cap also causesindexing of the strip and piercing of an aligned blister.

It will be appreciated that the inhaler of the invention may be either apassive or active device. In a passive device, the dose is entrained ina flow of air caused when the user inhales through the mouthpiece.However, in an active device, the inhaler would include means forgenerating a pressurised flow of gas or air through the blister toentrain the dose and carry it out of the blister through the mouthpieceand into the user's airway. In one embodiment, the inhaler may beprovided with a source of pressurised gas or air within the housing.

Reference is made throughout this specification to both “unused” and“used” blisters. It will be appreciated that “unused” blisters refer tothose blisters that have not passed the blister piercing member andwhich remain intact with the dose contained therein. “Used” blistersrefer to those blisters which have passed the blister piercing member inresponse to movement of the actuator by a user and which have beenpierced to enable access to the dose contained therein to be obtained.Although in general, a “used” blister refers to a blister from which adose has been inhaled, it should also be taken to include blisters whichhave passed the blister piercing member and have been pierced but whichstill contain either some or all of the dose contained therein. This mayhappen, for example, when a user moves the actuator to move the blisterstrip without inhaling the dose from a previously pierced blister.

The invention claimed is:
 1. An inhaler, comprising a housing, amouthpiece through which a dose of medicament is inhaled by a user, ablister strip having a plurality of blisters, each blister containing,at least initially, a dose of medicament for inhalation by a user, ablister opening assembly for facilitating withdrawal of medicament froma target blister of the blister strip, an actuator mechanism operable tosequentially move each blister into alignment with the blister openingassembly so as to become said target blister, the housing comprising afirst blister compartment for storing an unopened portion of the blisterstrip as a first coil, a second blister compartment for receiving anopened portion of the blister strip and coiling it into a second coil,and a movable dividing wall separating the first and second blistercompartments, the movable dividing wall being displaced progressivelyduring successive actuations of the inhaler, thereby causing the volumeof the first blister compartment to decrease progressively and thevolume of the second blister compartment to increase progressively, theinhaler further comprising a first arcuate supporting surface which isdisposed in, or forms part of, the first blister compartment within thehousing for supporting at least a portion of the first coil, wherein aradius of the first arcuate supporting surface matches the radius of thefirst coil, at a stage in the life of the inhaler, when the diameter ofthe first coil is at a maximum and a blister strip guide rib forcontrolling the direction of the used blister strip as it enters thesecond blister compartment and for coiling the used blister strip backon itself so that a leading edge engages the used blister strip enteringthe second blister compartment to augment the movement of the blisterstrip forward, with a section of the used blister strip passing betweenthe guide rib and an internal surface of the housing during successiveactuations of the inhaler, wherein the blister strip has a height a whenit is located in the second blister compartment and the guide rib isspaced apart from the internal surface of the housing by distance b toform a channel through which the section of the blister strip passes,wherein the section of the blister strip passing between the guide riband the internal surface of the housing does not include a blister bowlwhich contained the dose of medicament before being opened,characterized in-that the blister height a as the section of the blisterstrip passes through the channel is greater than the distance b of thechannel.
 2. The inhaler as claimed in claim 1, comprising a secondarcuate supporting surface which is disposed in, or forms part of, thesecond blister compartment within the housing for supporting at least aportion of the second coil, wherein a radius of the second arcuatesupporting surface matches the radius of the second coil, at a stage inthe life of the inhaler, when the diameter of the first coil is at ornear a maximum.
 3. The inhaler as claimed in claim 2, comprising a thirdarcuate supporting surface which is disposed in, or forms part of, thefirst blister compartment within the housing for supporting at least aportion of the first coil, wherein a radius of the third arcuatesupporting surface matches the radius of the first coil, at a stage inthe life of the inhaler, when the sum diameter of the first and secondcoils is at a maximum.
 4. The inhaler as claimed in claim 3, wherein thearcuate supporting surfaces extend from an internal surface of thehousing.
 5. The inhaler as claimed in claim 3, wherein the arcuatesupporting surfaces extend from an internal wall disposed within thehousing.
 6. The inhaler as claimed in claim 3, wherein the first and/orthird arcuate supporting surfaces have a length equivalent to an arc ofthe first coil of at least 30 degrees when the radius of the first coilis at a maximum.
 7. The inhaler as claimed in claim 3, wherein thepositions of the arcuate supporting surfaces relative to the housing arefixed such that they are immoveable.
 8. The inhaler as claimed in claim3, wherein the first coil is disposed intermediate the third arcuatesupporting surface and the moveable dividing wall.
 9. The inhaler asclaimed in claim 2, wherein the second coil is disposed intermediate thesecond arcuate supporting surface and the moveable dividing wall. 10.The inhaler as claimed claim 1, further comprising a blister crushingmember for at least partially squashing the blisters after they havebeen opened.
 11. The inhaler as claimed in claim 3, wherein the secondarcuate supporting surface has a length equivalent to an arc of thesecond coil of at least 30 degrees when the radius of the first coil isat a maximum.
 12. The inhaler as claimed in claim 1, wherein themoveable dividing wall comprises an elongate foot which is attached toand integrally formed with a baffle.
 13. The inhaler as claimed in claim12, wherein the baffle has a linear body portion and an arcuate tailportion extending from a lower end of the linear body portion.